RESUMO
OBJECTIVES: The aim of our study was to establish if 48-hour ambulatory blood pressure monitoring (ABPM) is more reliable than 24-hour monitoring in order to reduce the impact of external factors on blood pressure (BP) in children. METHODS: Two hundred fifteen children with indications for ABPM underwent 48-hour ABPM. In the first part of the study, the values of systolic BP (SBP), diastolic BP (DBP) and heart rate between the first 24 hours and the total 48 hours were compared. In the second part, the same parameters between the first and second 24 hours were compared. In the third part, we determined whether the differences in measurements between the first and second 24 hours had clinical significance and meant a change of diagnosis. RESULTS: The results of the first part of the study showed no statistically significant differences. In the second part, the average values of SBP and DBP were statistically significantly higher during the first 24 hours as compared with the second 24 hours. In the second 24 hours, more children had normal BP (NBP) and a smaller number of them had high NBP or arterial hypertension (AH) compared with the first 24 hours, suggesting that this has clinical significance. CONCLUSIONS: Within certain limits, the results of our study suggest that 48-hour ABPM is more reliable than 24-hour ABPM, where especially the second 24 hours are a period of measurement that should be taken into consideration for this purpose. These results could impact the diagnostics of AH in children.